The easy way is to use the CRTL button to multi-select the 11 solids and DELETE them. Turn off the option to delete the children, before you hit OK.
It looks like the 11 solids are parents to many other features, so you will probably get many Update Errors. One solution to these errors is to Isolate all the features with errors.
Based on the attached picture, I think the best solution is to just Hide the 11 solids, and don't delete them.
This is an interesting looking part - what is it?